NYC Master Plumber License Exam Questions
With Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the minimum slope required for a 3-inch horizontal
drainpipe to ensure proper drainage?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
C) 1/4 inch per foot
This slope ensures gravity drainage without risking clogging.
2. Which of the following materials is generally approved for potable
water supply in NYC?
A) Polyvinyl chloride (PVC)
B) Copper
C) Cast iron
D) Galvanized steel
B) Copper
Copper is widely approved for potable water due to its durability
and safety.
3. A backflow preventer is required to protect which type of water
system?
A) Stormwater
B) Non-potable water
C) Potable water
D) Condensate
, C) Potable water
Backflow preventers prevent contamination of the potable water
supply.
4. The maximum spacing for supports of horizontal copper water
tubing 1 inch in diameter is:
A) 4 feet
B) 6 feet
C) 8 feet
D) 10 feet
B) 6 feet
Proper support spacing prevents sagging and stress on the joints.
5. Which type of valve is most suitable for isolating a section of pipe
without pressure drop?
A) Gate valve
B) Globe valve
C) Check valve
D) Ball valve
D) Ball valve
Ball valves provide quick shutoff with minimal flow restriction.
6. In NYC, the minimum water pressure at the building entrance for
domestic service is typically:
A) 20 psi
B) 30 psi
C) 40 psi
D) 50 psi
B) 30 psi
, Building codes require adequate pressure for normal fixture
operation.
7. What is the primary function of a vent in a drainage system?
A) Reduce water flow
B) Prevent sewer gas entry
C) Increase pipe capacity
D) Support the drainpipe
B) Prevent sewer gas entry
Vents allow sewer gases to escape safely and maintain trap seals.
8. The NYC Plumbing Code requires that water heaters be installed:
A) Outdoors only
B) In accessible locations for maintenance
C) Only in basements
D) Directly above fixtures
B) In accessible locations for maintenance
Accessibility ensures proper inspection, maintenance, and
replacement.
9. For a one-family dwelling, the minimum size of a water service
pipe is:
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1 1/2 inch
B) 3/4 inch
This size provides sufficient water supply for standard domestic
needs.
With Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the minimum slope required for a 3-inch horizontal
drainpipe to ensure proper drainage?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
C) 1/4 inch per foot
This slope ensures gravity drainage without risking clogging.
2. Which of the following materials is generally approved for potable
water supply in NYC?
A) Polyvinyl chloride (PVC)
B) Copper
C) Cast iron
D) Galvanized steel
B) Copper
Copper is widely approved for potable water due to its durability
and safety.
3. A backflow preventer is required to protect which type of water
system?
A) Stormwater
B) Non-potable water
C) Potable water
D) Condensate
, C) Potable water
Backflow preventers prevent contamination of the potable water
supply.
4. The maximum spacing for supports of horizontal copper water
tubing 1 inch in diameter is:
A) 4 feet
B) 6 feet
C) 8 feet
D) 10 feet
B) 6 feet
Proper support spacing prevents sagging and stress on the joints.
5. Which type of valve is most suitable for isolating a section of pipe
without pressure drop?
A) Gate valve
B) Globe valve
C) Check valve
D) Ball valve
D) Ball valve
Ball valves provide quick shutoff with minimal flow restriction.
6. In NYC, the minimum water pressure at the building entrance for
domestic service is typically:
A) 20 psi
B) 30 psi
C) 40 psi
D) 50 psi
B) 30 psi
, Building codes require adequate pressure for normal fixture
operation.
7. What is the primary function of a vent in a drainage system?
A) Reduce water flow
B) Prevent sewer gas entry
C) Increase pipe capacity
D) Support the drainpipe
B) Prevent sewer gas entry
Vents allow sewer gases to escape safely and maintain trap seals.
8. The NYC Plumbing Code requires that water heaters be installed:
A) Outdoors only
B) In accessible locations for maintenance
C) Only in basements
D) Directly above fixtures
B) In accessible locations for maintenance
Accessibility ensures proper inspection, maintenance, and
replacement.
9. For a one-family dwelling, the minimum size of a water service
pipe is:
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1 1/2 inch
B) 3/4 inch
This size provides sufficient water supply for standard domestic
needs.
